read(DAVID_IAN);

avoid := {

[0,0,0],
[1,1,1],

[0,1,0,1,0],
[1,0,1,0,1],

[0,0,1,0,0,1,0,0],
[0,1,0,0,1,0,0,1],
[0,1,1,0,1,1,0,1],
[1,0,0,1,0,0,1,0],
[1,0,1,1,0,1,1,0],
[1,1,0,1,1,0,1,1],

[0,0,1,1,0,0,1,1,0,0],
[0,1,1,0,0,1,1,0,0,1],
[1,0,0,1,1,0,0,1,1,0],
[1,1,0,0,1,1,0,0,1,1],

[0,0,1,0,1,1,0,0,1,0,1,1,0,0,1],
[0,0,1,1,0,1,0,0,1,1,0,1,0,0,1],
[0,1,0,0,1,1,0,1,0,0,1,1,0,1,0],
[0,1,0,1,1,0,0,1,0,1,1,0,0,1,0],
[0,1,1,0,0,1,0,1,1,0,0,1,0,1,1],
[0,1,1,0,1,0,0,1,1,0,1,0,0,1,1],
[1,0,0,1,0,1,1,0,0,1,0,1,1,0,0],
[1,0,0,1,1,0,1,0,0,1,1,0,1,0,0],
[1,0,1,0,0,1,1,0,1,0,0,1,1,0,1],
[1,0,1,1,0,0,1,0,1,1,0,0,1,0,1],
[1,1,0,0,1,0,1,1,0,0,1,0,1,1,0],
[1,1,0,1,0,0,1,1,0,1,0,0,1,1,0],

[0,0,1,0,0,1,1,0,0,1,0,0,1,1,0,0,1],
[0,0,1,1,0,0,1,0,0,1,1,0,0,1,0,0,1],
[0,0,1,1,0,1,1,0,0,1,1,0,1,1,0,0,1],
[0,1,0,0,1,1,0,0,1,0,0,1,1,0,0,1,0],
[0,1,1,0,0,1,0,0,1,1,0,0,1,0,0,1,1],
[0,1,1,0,0,1,1,0,1,1,0,0,1,1,0,1,1],
[0,1,1,0,1,1,0,0,1,1,0,1,1,0,0,1,1],
[1,0,0,1,0,0,1,1,0,0,1,0,0,1,1,0,0],
[1,0,0,1,1,0,0,1,0,0,1,1,0,0,1,0,0],
[1,0,0,1,1,0,1,1,0,0,1,1,0,1,1,0,0],
[1,0,1,1,0,0,1,1,0,1,1,0,0,1,1,0,1],
[1,1,0,0,1,0,0,1,1,0,0,1,0,0,1,1,0],
[1,1,0,0,1,1,0,1,1,0,0,1,1,0,1,1,0],
[1,1,0,1,1,0,0,1,1,0,1,1,0,0,1,1,0],

[0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1],
[0,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0],
[0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,0],
[0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1],
[1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0],
[1,0,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,1],
[1,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,0,1],
[1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0],

[0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0],
[0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1],
[0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0],
[0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0],
[0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0],
[1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1],
[1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1],
[1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1],
[1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0],
[1,1,0,1,1,0,0,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,1]


 };

GJseries(2,avoid,30);

f := GJs({0,1}, avoid,x);

d := denom(f);

q := degree(d,x);

p := expand(y^q*subs(x=1/y,d));

t := fsolve(p=0,y);

max(t);